JP6897372B2 - Heat exchanger - Google Patents

Description

The present invention relates to a heat exchanger.

Conventionally, it is provided with a plurality of flat multi-hole pipes and fins joined to the plurality of flat multi-hole pipes, and heat exchange allows the refrigerant flowing inside the flat multi-hole pipes to exchange heat with the air flowing outside the flat multi-hole pipes. The vessel is known.

For example, Patent Document 1 (Japanese Unexamined Patent Publication No. 2012-233680) proposes a heat exchanger in which a plurality of cut-up pieces are provided in a portion between flat multi-hole tubes in a fin to improve the heat transfer performance of the fin. Has been done.

In the heat exchanger shown in Patent Document 1, when the fins and the flat multi-hole tube are brazed and joined, the fins are annealed to reduce the strength. Therefore, the fins and the flat multi-hole tube are reduced in strength. The problem is that the fins will buckle when the entire heat exchanger in the state of being joined is bent, and the fins are provided by providing a flat portion in which no cut-up pieces are formed in the continuous portion of the fins. It suppresses the buckling of.

However, when the flat multi-hole tube is inserted into the fin, which is a stage prior to the brazing stage between the fin and the flat multi-hole tube, friction is generated between the fin and the flat multi-hole tube, which causes strong stress on the fin. May work. In particular, when a cut-up piece is formed on the fin in order to improve heat transfer performance, the stress generated when the flat multi-hole tube is inserted is concentrated near the end of the cut-up piece, and the seat of the fin is seated at the location. It is easy to bend.

The present invention has been made in view of the above points, and an object of the present invention is to suppress buckling in the vicinity of the cut-up piece when the flat tube is inserted into the fin on which the cut-up piece is formed. The purpose is to provide a heat exchanger that can be made to operate.

The heat exchanger according to the first aspect includes a plurality of flat tubes and a plurality of fins. The plurality of flat tubes are arranged so that the flat surfaces of the flat tubes face each other. The fin has an insertion portion. The insertion portion extends along the insertion direction, and at least a part of the flat tube is inserted. The insertion direction is a direction that intersects both the direction in which the flat tubes are arranged and the longitudinal direction of the flat tubes. The fin has a cut-up piece and a rib. The cut-up piece is cut up in the plate thickness direction between the plurality of insertion portions. The rib is formed between the insertion portion and the cut-up piece.

The insertion direction is not particularly limited, and may be, for example, a direction slightly inclined without being orthogonal to the direction in which the flat tubes are arranged, or with respect to the longitudinal direction of the flat tubes. It may be in a slightly inclined direction without being orthogonal to each other. The inclination angle can be, for example, 45 degrees or less.

Further, the cut-up piece is not particularly limited, and may be, for example, a louver cut up so that the leeward side is open and the leeward side is not open, or an opening is provided on both the leeward side and the leeward side. It may be a slit cut up to be formed. The opening on the leeward side and the opening on the leeward side of the slit may be formed on the same side in the plate thickness direction of the fins, or may be formed on different sides from each other.

Further, the rib is not particularly limited, and may be formed between the insertion portion and the cut-up piece along the insertion direction, and the rib is formed so that the insertion direction is the longitudinal direction of the rib. You may.

In this heat exchanger, since the fins are formed with cut-up pieces, the heat transfer performance of heat exchange can be improved. Here, when the flat tube is inserted into the fin on which the cut-up piece is formed in this way, stress is generated in the fin due to the friction generated between the fin and the flat tube, and in particular, the cut-up piece of the cut-up piece Of these, stress is concentrated in a portion close to the portion where the friction occurs, and there is a possibility that buckling of the fin may occur starting from the portion.

On the other hand, in this heat exchanger, ribs are formed between the insertion portion and the cut-up piece, so that the stress concentration in the vicinity of the cut-up piece of the fin when inserting the flat tube is alleviated. , It becomes possible to suppress buckling in the vicinity of the cut-up piece of the fin.

The heat exchanger according to the second aspect is the heat exchanger according to the first aspect, and the rib is at least the portion of the insertion portion of the fin where the flat tube first hits when the flat tube is inserted into the fin. It is formed on the insertion progress side in the insertion direction.

In this heat exchanger, ribs are formed in a place where stress tends to be concentrated in the fin when the flat tube is inserted, that is, a place on the insertion progress side of the place where the flat tube first hits the fin when the flat tube is inserted. Therefore, it is possible to relieve the stress in the fin where the stress tends to be concentrated when the flat tube is inserted.

The heat exchanger according to the third aspect is the heat exchanger according to the first aspect or the second aspect, and the fins have a plurality of cut pieces so as to be arranged in the insertion direction of the flat tube. The rib extends continuously between the insertion portion and the plurality of cut pieces along the insertion direction of the flat tube.

It is preferable that the ribs extend in a row so as to include a range in which each cut-up piece exists, at least in the insertion direction of the flat tube.

Further, the case of extending along the insertion direction is not limited to the case where the rib extends in parallel with the insertion direction, and includes, for example, the case where the longitudinal direction of the rib and the insertion direction are parallel or substantially parallel.

The fins of this heat exchanger are provided with a plurality of cut-up pieces so as to line up in the insertion direction of the flat tube. Therefore, it is possible to improve the heat transfer performance of the fins.

Here, for example, when a plurality of cut-up pieces are provided side by side in the fin, even if a rib is formed only between one of the cut-up pieces and the insertion portion, the other cut-up pieces are formed. Buckling may occur when inserting a flat tube near the end of one piece.

On the other hand, in this heat exchanger, since the ribs extend continuously along the insertion direction of the flat tube between the insertion portion and the plurality of cut pieces, a plurality of cut pieces are provided. Even when the fins are used, it is possible to suppress buckling in the vicinity of the end of each cut-up piece.

The heat exchanger according to the fourth aspect is the heat exchanger according to the third aspect, and the rib is the most inserted in the insertion direction of the flat tube among the plurality of cut pieces located between the adjacent insertion portions. It extends from the cut-up piece located on the side to the insertion progress side.

In this heat exchanger, it is possible to suppress buckling in the vicinity of the ends of all of the plurality of cut pieces located between the adjacent insertion portions.

The heat exchanger according to the fifth aspect is the heat exchanger according to any one of the first to fourth aspects, and the fins are formed so as to border the insertion portion and are formed on the flat surface of the flat tube. It has opposite fin collars. The rib is formed between the fin collar and the cut piece.

The insertion portion of the fin and the flat surface of the flat tube may be in direct contact with each other or may be in contact with each other via a brazing material or the like.

For example, the thickness of the fins of the fin collar in the plate thickness direction is preferably larger than the thickness of the fins adjacent to the fin collar in the plate thickness direction.

In this heat exchanger, the fins have a fin collar that faces the flat surface of the flat tube. Therefore, when the flat tube is inserted, a large friction is likely to occur between the flat surface of the flat tube and the fin collar of the fin, and a larger stress concentration is likely to occur in the vicinity of the end portion of the cut-up piece of the fin.

On the other hand, in this heat exchanger, ribs are formed between the fin collar and the cut-up piece, so even if a large stress acts through the fin collar when inserting the flat tube, the large stress is applied. It is possible to suppress the concentration of the fins and suppress the buckling of the fins.

The heat exchanger according to the sixth aspect is the heat exchanger according to any one of the first to fifth aspects, and the fin has ribs formed between the cut-up piece and the insertion portions on both sides. There is.

In this heat exchanger, ribs are formed both between the insertion portion located on one side of the cut-up piece and between the insertion portion located on the other side of the cut-up piece. Therefore, it is possible to suppress buckling in the vicinity of both ends of the cut-up piece.

The heat exchanger according to the seventh aspect is the heat exchanger according to any one of the first to sixth aspects, and the ribs are formed by raising the fins in the plate thickness direction.

The ribs formed by the ridges are formed, for example, from the rising portion, the top, and the top, which rise up to the top toward one side in the plate thickness direction when viewed from the nearest insertion portion side. It may be configured to have a falling portion that falls toward the opposite side in the plate thickness direction. Here, the position of the rising portion in the plate thickness direction before rising and the position in the falling portion in the plate thickness direction after falling may be the same or different.

In this heat exchanger, since the ribs are formed by raising the fins in the plate thickness direction, it is possible to increase the strength of the ribs.

In the heat exchanger according to the first aspect, it is possible to improve the heat transfer performance by the cut-up piece and suppress buckling in the vicinity of the cut-up piece of the fin when the flat tube is inserted.

In the heat exchanger according to the second aspect, it is possible to relieve the stress in the fin where the stress tends to be concentrated when the flat tube is inserted.

In the heat exchanger according to the third aspect, it is possible to suppress buckling in the vicinity of the end portion of each cut-up piece even when a fin provided with a plurality of cut-up pieces is used.

In the heat exchanger according to the fourth aspect, it is possible to suppress buckling in the vicinity of the end portion of all of the plurality of cut-up pieces located between the adjacent insertion portions.

In the heat exchanger according to the fifth aspect, even if a large stress acts through the fin collar when the flat tube is inserted, it is possible to suppress the concentration of the large stress and suppress the buckling of the fin.

In the heat exchanger according to the sixth aspect, it is possible to suppress buckling in the vicinity of both ends of the cut-up piece.

In the heat exchanger according to the seventh aspect, it is possible to increase the strength of the ribs.

It is a schematic block diagram of the air conditioner which adopted the heat exchanger which concerns on one Embodiment of this invention. It is an external perspective view of an outdoor unit. It is a schematic perspective view of an outdoor heat exchanger. It is a block diagram for demonstrating the refrigerant flow of an outdoor heat exchanger. It is a partially enlarged view of the heat exchange part of FIG. It is a figure which shows the state which the fin is attached to the flat multi-hole pipe 63 as seen from the longitudinal direction of a flat multi-hole pipe 63. It is a figure which shows the state in which a flat multi-hole tube is inserted into a fin. It is a figure which shows the shape of the fin in the insertion direction view of a flat multi-hole tube. It is a figure which shows the shape of the fin seen from the direction perpendicular to both the insertion direction of a flat multi-hole tube and the plate thickness direction of a fin. It is a figure which shows the state which the fin of the heat exchanger which concerns on the modification A is attached to a flat multi-hole pipe. It is a figure which shows the state which the fin of the heat exchanger which concerns on the modification B is attached to a flat multi-hole pipe. It is a figure which shows the state which the fin of the heat exchanger which concerns on the modification C is attached to a flat multi-hole pipe.

Hereinafter, an embodiment of an air conditioner in which an outdoor heat exchanger as a heat exchanger according to the present invention is adopted and a modification thereof will be described with reference to the drawings. The specific configuration of the outdoor heat exchanger as the heat exchanger according to the present invention is not limited to the following embodiments and modifications thereof, and can be changed without departing from the gist of the invention.

(1) Configuration of Air Conditioner FIG. 1 shows a schematic configuration diagram of an air conditioner 1 in which an outdoor heat exchanger 11 as a heat exchanger according to an embodiment of the present invention is adopted.

The air conditioner 1 is a device capable of cooling and heating a room such as a building by performing a vapor compression refrigeration cycle. The air conditioner 1 mainly includes the outdoor unit 2, the indoor units 3a and 3b, the liquid refrigerant connecting pipe 4 and the gas refrigerant connecting pipe 5 connecting the outdoor unit 2 and the indoor units 3a and 3b, the outdoor unit 2 and the outdoor unit 2. It has a control unit 23 that controls the constituent devices of the indoor units 3a and 3b. The vapor compression type refrigerant circuit 6 of the air conditioner 1 is configured by connecting the outdoor unit 2 and the indoor units 3a and 3b via the refrigerant connecting pipes 4 and 5.

The outdoor unit 2 is installed outdoors (on the roof of the building, near the wall surface of the building, etc.) and constitutes a part of the refrigerant circuit 6. The outdoor unit 2 mainly includes an accumulator 7, a compressor 8, a four-way switching valve 10, an outdoor heat exchanger 11, an outdoor expansion valve 12 as an expansion mechanism, a liquid side closing valve 13, and a gas side closing valve. It has 14 and an outdoor fan 15. Each device and the valve are connected by a refrigerant pipe 16 to 22.

The indoor units 3a and 3b are installed indoors and form a part of the refrigerant circuit 6. The indoor unit 3a mainly includes an indoor expansion valve 31a, an indoor heat exchanger 32a, and an indoor fan 33a. The indoor unit 3b mainly has an indoor expansion valve 31b as an expansion mechanism, an indoor heat exchanger 32b, and an indoor fan 33b.

One end of the liquid refrigerant connecting pipe 4 is connected to the liquid side closing valve 13 of the outdoor unit 2, and the other end is connected to the liquid side ends of the indoor expansion valves 31a and 31b of the indoor units 3a and 3b. One end of the gas refrigerant connecting pipe 5 is connected to the gas side closing valve 14 of the outdoor unit 2, and the other end is connected to the gas side ends of the indoor heat exchangers 32a and 32b of the indoor units 3a and 3b.

The control unit 23 is configured by communicating with a control board or the like (not shown) provided on the outdoor unit 2 or the indoor units 3a and 3b. In addition, in FIG. 1, for convenience, it is shown at a position away from the outdoor unit 2 and the indoor units 3a and 3b. The control unit 23 controls the constituent devices 8, 10, 12, 15, 31a, 31b, 33a, 33b of the air conditioner 1 (here, the outdoor unit 2 and the indoor units 3a and 3b), that is, the air conditioner 1. It is designed to control the overall operation.

(2) Operation of the air conditioner Next, the operation of the air conditioner 1 will be described with reference to FIG. In the air conditioner 1, the compressor 8, the outdoor heat exchanger 11, the outdoor expansion valve 12, the indoor expansion valves 31a, 31b, the indoor heat exchangers 32a, 32b, and the cooling operation in which the refrigerant flows in this order, and the compressor 8, the indoor heat. A heating operation is performed in which the refrigerant flows in the order of the exchangers 32a and 32b, the indoor expansion valves 31a and 31b, the outdoor expansion valve 12, and the outdoor heat exchanger 11. The cooling operation and the heating operation are performed by the control unit 23.

During the cooling operation, the four-way switching valve 10 is switched to the outdoor heat dissipation state (the state shown by the solid line in FIG. 1). In the refrigerant circuit 6, the low-pressure gas refrigerant in the refrigeration cycle is sucked into the compressor 8, compressed to a high pressure in the refrigeration cycle, and then discharged. The high-pressure gas refrigerant discharged from the compressor 8 is sent to the outdoor heat exchanger 11 through the four-way switching valve 10. The high-pressure gas refrigerant sent to the outdoor heat exchanger 11 is radiated by exchanging heat with the outdoor air supplied as a cooling source by the outdoor fan 15 in the outdoor heat exchanger 11 that functions as a radiator of the refrigerant. , Becomes a high-pressure liquid refrigerant. The high-pressure liquid refrigerant radiated by the outdoor heat exchanger 11 is sent to the indoor expansion valves 31a and 31b through the outdoor expansion valve 12, the liquid side closing valve 13, and the liquid refrigerant connecting pipe 4. The refrigerant sent to the indoor expansion valves 31a and 31b is depressurized to the low pressure of the refrigeration cycle by the indoor expansion valves 31a and 31b to become a low-pressure gas-liquid two-phase state refrigerant. The low-pressure gas-liquid two-phase refrigerant decompressed by the indoor expansion valves 31a and 31b is sent to the indoor heat exchangers 32a and 32b. The low-pressure gas-liquid two-phase refrigerant sent to the indoor heat exchangers 32a and 32b exchanges heat with the indoor air supplied as a heating source by the indoor fans 33a and 33b in the indoor heat exchangers 32a and 32b. Evaporates. As a result, the indoor air is cooled, and then the indoor air is supplied to the room to cool the room. The low-pressure gas refrigerant evaporated in the indoor heat exchangers 32a and 32b is sucked into the compressor 8 again through the gas refrigerant connecting pipe 5, the gas side closing valve 14, the four-way switching valve 10, and the accumulator 7.

During the heating operation, the four-way switching valve 10 is switched to the outdoor evaporation state (the state shown by the broken line in FIG. 1). In the refrigerant circuit 6, the low-pressure gas refrigerant in the refrigeration cycle is sucked into the compressor 8, compressed to a high pressure in the refrigeration cycle, and then discharged. The high-pressure gas refrigerant discharged from the compressor 8 is sent to the indoor heat exchangers 32a and 32b through the four-way switching valve 10, the gas side closing valve 14, and the gas refrigerant connecting pipe 5. The high-pressure gas refrigerant sent to the indoor heat exchangers 32a and 32b exchanges heat with the indoor air supplied as a cooling source by the indoor heat exchangers 33a and 33b in the indoor heat exchangers 32a and 32b to dissipate heat. It becomes a high-pressure liquid refrigerant. As a result, the room air is heated, and then the room is heated by being supplied to the room. The high-pressure liquid refrigerant radiated by the indoor heat exchangers 32a and 32b is sent to the outdoor expansion valve 12 through the indoor expansion valves 31a and 31b, the liquid refrigerant connecting pipe 4 and the liquid side closing valve 13. The refrigerant sent to the outdoor expansion valve 12 is depressurized to the low pressure of the refrigeration cycle by the outdoor expansion valve 12 to become a low-pressure gas-liquid two-phase state refrigerant. The low-pressure gas-liquid two-phase refrigerant decompressed by the outdoor expansion valve 12 is sent to the outdoor heat exchanger 11. The low-pressure gas-liquid two-phase refrigerant sent to the outdoor heat exchanger 11 exchanges heat with the outdoor air supplied as a heating source by the outdoor fan 15 in the outdoor heat exchanger 11 that functions as a refrigerant evaporator. It goes and evaporates to become a low pressure gas refrigerant. The low-pressure refrigerant evaporated in the outdoor heat exchanger 11 is sucked into the compressor 8 again through the four-way switching valve 10 and the accumulator 7.

In the state where the outdoor heat exchanger 11 is functioning as a refrigerant evaporator during the heating operation, if the outside air temperature or the refrigerant evaporation temperature satisfies the predetermined operating condition conditions, the outdoor heat exchanger 11 is frosted. May adhere. If a large amount of the frost adheres, the air supplied from the outdoor fan 15 receives an excessive ventilation resistance when passing through the outdoor heat exchanger 11 to which the frost adheres, and the heat exchange efficiency decreases. There is a risk that it will end up. Therefore, when a predetermined defrost determination condition such as a state in which the predetermined operation condition condition is satisfied continues for a predetermined time or longer is satisfied, the control unit 23 puts the four-way switching valve 10 in an outdoor heat dissipation state (in the solid line of FIG. 1). Switch to the indicated state) and perform defrost operation. When the defrosting process is completed, such as when the defrosting operation is performed for a predetermined time, the control unit 23 again switches the four-way switching valve 10 to the outdoor evaporation state (the state shown by the broken line in FIG. 1) to perform the heating operation. To resume.

(3) Configuration of Outdoor Unit FIG. 2 shows an external perspective view of the outdoor unit 2. FIG. 3 shows a schematic perspective view of the outdoor heat exchanger 11. FIG. 4 shows a configuration diagram for explaining the refrigerant flow in the outdoor heat exchanger 11.

(3-1) Overall Configuration The outdoor unit 2 is a top-blown heat exchange unit that sucks air from the side surface of the casing 40 and blows air out from the top surface of the casing 40. The outdoor unit 2 mainly includes a substantially rectangular parallelepiped box-shaped casing 40, an outdoor fan 15 as a blower, devices 7, 8, 11 such as a compressor and an outdoor heat exchanger, a four-way switching valve, an outdoor expansion valve, and the like. It has a refrigerant circuit component including valves 10, 12 to 14, refrigerant pipes 16 to 22, and the like, which constitutes a part of the refrigerant circuit 6. In the following description, "top", "bottom", "left", "right", "front", "rear", "front", and "back" are shown in FIG. 2 unless otherwise specified. It means the direction when the outdoor unit 2 is viewed from the front (left diagonal front side in the drawing).

The casing 40 mainly includes a bottom frame 42 spanning on a pair of installation legs 41 extending in the left-right direction, a support column 43 extending vertically from a corner of the bottom frame 42, and a fan module 44 attached to the upper end of the support column 43. And a front panel 45, and air suction ports 40a, 40b, 40c are formed on the side surfaces (here, the back surface and both left and right side surfaces), and an air outlet 40d is formed on the top surface.

The bottom frame 42 forms the bottom surface of the casing 40, and the outdoor heat exchanger 11 is provided on the bottom frame 42. Here, the outdoor heat exchanger 11 is a heat exchanger having a substantially U-shape in a plan view facing the back surface and the left and right side surfaces of the casing 40, and substantially forms the back surface and the left and right side surfaces of the casing 40. ..

A fan module 44 is provided on the upper side of the outdoor heat exchanger 11 to form a front surface, a back surface of the casing 40, a portion above the columns 43 on both the left and right sides, and a top surface of the casing 40. .. Here, the fan module 44 is an aggregate in which the outdoor fan 15 is housed in a substantially rectangular parallelepiped box body in which the upper surface and the lower surface are open. The opening on the top surface of the fan module 44 is an outlet 40d, and the outlet 40d is provided with an outlet grill 46. The outdoor fan 15 is arranged in the casing 40 facing the air outlet 40d, and is a blower that takes in air into the casing 40 from the suction ports 40a, 40b, 40c and discharges the air from the air outlet 40d.

The front panel 45 is bridged between the columns 43 on the front side and forms the front surface of the casing 40.

Refrigerant circuit components other than the outdoor fan 15 and the outdoor heat exchanger 11 (accumulator 7, compressor 8 and refrigerant pipes 16 to 18 are shown in FIG. 2) are also housed in the casing 40. Here, the compressor 8 and the accumulator 7 are provided on the bottom frame 42.

As described above, the outdoor unit 2 has a casing 40 in which air suction ports 40a, 40b, 40c are formed on the side surfaces (here, the back surface and both left and right side surfaces) and an air outlet 40d is formed on the top surface, and the casing 40. It has an outdoor fan 15 arranged inside the air outlet 40d and an outdoor heat exchanger 11 arranged below the outdoor fan 15 in the casing 40.

(3-2) Outdoor Heat Exchanger The outdoor heat exchanger 11 is a heat exchanger that exchanges heat between the refrigerant and the outdoor air, and mainly includes a first header collecting pipe 80, a second header collecting pipe 90, and the like. It has a plurality of flat multi-hole tubes 63 and a plurality of fins 70. Here, the first header collecting pipe 80, the second header collecting pipe 90, the flat multi-hole pipe 63, and the fin 70 are all made of aluminum or an aluminum alloy, and are joined to each other by brazing or the like.

The detailed structure of the flat multi-hole tube 63 and the fin 70 will be described later.

Both the first header collecting pipe 80 and the second header collecting pipe 90 are vertically elongated hollow cylindrical members. The first header collecting pipe 80 is erected on one end side of the outdoor heat exchanger 11 (here, the left front end side in FIG. 3), and the second header collecting pipe 90 is the other end of the outdoor heat exchanger 11. It is erected on the side (here, the right front end side in FIG. 3).

As shown in FIG. 3, the outdoor heat exchanger 11 has a heat exchange unit 60 formed by fixing fins 70 to a plurality of flat multi-hole pipes 63 arranged one above the other. The heat exchange unit 60 has an upper heat exchange unit 60A on the upper stage side and a lower heat exchange unit 60B on the lower stage side.

As shown in FIG. 4, the first header collecting pipe 80 is vertically partitioned by a partition plate 81 whose internal space is widened in the horizontal direction, whereby a gas side inlet / outlet communication space 80A and a liquid side inlet / outlet communication space 80B are formed. Has been done. A flat multi-hole pipe 63 constituting the corresponding upper heat exchange portion 60A communicates with the gas side inlet / outlet communication space 80A. Further, a flat multi-hole pipe 63 constituting the corresponding lower heat exchange portion 60B communicates with the liquid side inlet / outlet communication space 80B.

Further, a refrigerant pipe 19 (see FIG. 1) that sends the refrigerant sent from the compressor 8 to the gas side inlet / outlet communication space 80A during the cooling operation is connected to the gas side inlet / outlet communication space 80A of the first header collecting pipe 80. ..

Further, a refrigerant pipe 20 (see FIG. 1) for sending the refrigerant sent from the outdoor expansion valve 12 to the liquid side inlet / outlet communication space 80B during the heating operation is connected to the liquid side inlet / outlet communication space 80B of the first header collecting pipe 80. There is.

The second header collecting pipe 90 is provided between the partition plate 92 and the partition plate 93, while the internal space thereof is partitioned vertically by the partition plates 91, 92, 93, 94, respectively, which expand in the horizontal direction from the upper side. The first to third upper folded communication spaces 90A, 90B, 90C and the first to third lower folded communication spaces 90D, 90E, 90F arranged in order from the upper side by being separated vertically by the dividing plate 99 with a nozzle. Is formed. The flat multi-hole pipe 63 in the corresponding upper heat exchange section 60A communicates with the first to third upper folded communication spaces 90A, 90B, 90C, and the first to third lower folded communication spaces 90D, 90E, 90F. The flat multi-hole tube 63 in the corresponding lower heat exchange section 60B communicates with. The third upper-stage folded-back communication space 90C and the first lower-stage folded-back communication space 90D are vertically separated by a nozzle-equipped partition plate 99, but the nozzle 99a provided so as to penetrate vertically in the nozzle-equipped partition plate 99 is used. It communicates up and down through. Further, the first upper fold-back communication space 90A and the third lower fold-back communication space 90F are connected via the first connection pipe 24 connected to the second header collecting pipe 90, and the second upper fold-back communication space is connected. The 90B and the second lower folded communication space 90E are connected via a second connecting pipe 25 connected to the second header collecting pipe 90.

With the above configuration, when the outdoor heat exchanger 11 functions as a refrigerant evaporator, the refrigerant flowing from the refrigerant pipe 20 into the liquid side inlet / outlet communication space 80B of the first header collecting pipe 80 is the liquid side inlet / outlet communication space. It flows through the flat multi-hole pipe 63 of the lower heat exchange section 60B connected to the 80B, and flows into the first to third lower fold-back communication spaces 90D, 90E, 90F of the second header collecting pipe 90. The refrigerant flowing into the first lower folded communication space 90D flows into the third upper folded communication space 90C via the nozzle 99a of the partition plate 99 with a nozzle, and the upper heat exchange connected to the third upper folded communication space 90C. It flows into the gas side inlet / outlet communication space 80A of the first header collecting pipe 80 through the flat multi-hole pipe 63 of the portion 60A. The refrigerant that has flowed into the second lower folded communication space 90E flows into the second upper folded communication space 90B via the second connecting pipe 25, and is connected to the second upper folded communication space 90B. It flows into the gas side inlet / outlet communication space 80A of the first header collecting pipe 80 via the flat multi-hole pipe 63. The refrigerant that has flowed into the third lower folded communication space 90F flows into the first upper folded communication space 90A via the first connecting pipe 24, and is connected to the first upper folded communication space 90A. It flows into the gas side inlet / outlet communication space 80A of the first header collecting pipe 80 via the flat multi-hole pipe 63. The refrigerant merged in the gas side inlet / outlet communication space 80A of the first header collecting pipe 80 flows to the outside of the outdoor heat exchanger 11 via the refrigerant pipe 19.

When the outdoor heat exchanger 11 is used as a radiator for the refrigerant, the flow of the refrigerant is opposite to the above.

(4) Flat multi-hole tube FIG. 5 shows a partially enlarged view of the heat exchange section 60 shown in FIG. FIG. 6 shows a state in which the fin 70 is attached to the flat multi-hole pipe 63 as viewed from the longitudinal direction of the flat multi-hole pipe 63.

The flat multi-hole pipe 63 has flat flat surfaces 63a on the upper surface and the lower surface facing the vertical direction, which are heat transfer surfaces, and a large number of small passages 63b through which the refrigerant flows. The plurality of passages 63b included in the flat multi-hole pipe 63 are provided side by side in the air flow direction (longitudinal direction in the cross-sectional view of the passage 63b).

The flat multi-hole tube 63 is not particularly limited, but is manufactured by, for example, extrusion molding.

The plurality of flat multi-hole tubes 63 are arranged at predetermined intervals in the vertical direction.

In the flat multi-hole pipe 63, both ends of each passage 63b are connected to the first header collecting pipe 80 and the second header collecting pipe 90.

In the outdoor heat exchanger 11 of the present embodiment, the downstream end of the plurality of flat multi-hole pipes 63 in the air flow direction is located further downstream than the downstream end of the fin 70 in the air flow direction. It is configured in. Therefore, the structure of the outdoor heat exchanger 11 can be such that a part of the flat multi-hole pipe 63 is exposed to the leeward side instead of the fin 70. As a result, damage or breakage of the leeward end of the fin 70 during manufacturing or transportation of the outdoor heat exchanger 11 is suppressed. Further, when the outdoor heat exchanger 11 is bent using a tool such as a roller, the tool can be pressed against the flat multi-hole pipe 63 instead of the fin 70 to perform the work, so that the fin 70 may be deformed. Damage is suppressed. Further, when the outdoor heat exchanger 11 is brazed in the furnace, it can be brazed with the flat multi-hole pipe 63 grounded instead of the fin 70, so that the aluminum fin 70 is brazed at the time of brazing. Deformation due to thermal shrinkage and thermal expansion of the fins 70 that may occur when they come into contact with the floor surface in the furnace is also suppressed.

(5) Fins FIG. 7 shows how a flat multi-hole tube 63 is inserted into a fin 70.

The fins 70 are plate-shaped members that spread in the air flow direction and the vertical direction, and a plurality of fins 70 are arranged at predetermined intervals in the plate thickness direction and are fixed to the flat multi-hole pipe 63.

The fin 70 is formed so that a plurality of insertion portions 71 cut in the horizontal direction from the leeward side edge portion toward the leeward side to the front of the leeward side edge portion are arranged in the vertical direction. The insertion portion 71 is configured as an edge portion of the fin collar 71a formed by burring or the like on the flat multi-hole pipe 63 side. The shape of the insertion portion 71 substantially matches the outer shape of the cross section of the flat multi-hole pipe 63, and the flat multi-hole pipe 63 is brazed and fixed to the insertion portion 71 with the flat multi-hole pipe 63 inserted.

The fins 70 include a communication portion 70a that is continuous in the vertical direction and a plurality of windward portions 70b that extend downstream in the air flow direction from the communication portion 70a on the windward side of the flat multi-hole pipe 63. ,have. Here, it is preferable that the distance in the air flow direction from the upper end of the wind of the flat multi-hole pipe 63 to the upper end of the wind at the communication portion 70a of the fin 70 is 4 mm or more from the viewpoint of ensuring the frost bearing capacity. The lower part of the wind 70b is a portion surrounded in the vertical direction by adjacent insertion portions 71.

FIG. 8 shows the shape of the fin 70 in the insertion direction view of the flat multi-hole tube 63. FIG. 9 shows the shape of the fin 70 as viewed from a direction perpendicular to both the insertion direction of the flat multi-hole tube 63 and the plate thickness direction of the fin 70.

As shown in FIGS. 6 to 9, the fin 70 includes a waffle portion 72, a communication side fin tab 73, an insertion side fin tab 74, a slit 75, an insertion side rib 76, and a communication side rib 77, in addition to the above-mentioned insertion portion 71. , Main surface 79 and the like. The thickness of the main surface 79 in the plate thickness direction is, for example, 0.05 mm or more and 0.15 mm or less.

The insertion portion 71 extends along an insertion direction that intersects the direction in which the flat multi-hole pipes 63 are arranged and the longitudinal direction of the flat multi-hole pipes 63. The length of the insertion portion 71 in the insertion direction is shorter than the length of the flat multi-hole tube 63 in the insertion direction, and only a part of the flat multi-hole tube 63 is inserted. The insertion portion 71 is configured as a portion of the fin collar 71a on the flat multi-hole pipe 63 side. The fin collar 71a is erected with respect to the main surface 79 of the fin 70 so as to face the periphery including the flat surface 63a of the flat multi-hole pipe 63. Although not particularly limited, the height of the fin collar 71a in the direction perpendicular to the main surface 79 may be formed to be higher than the height of the slit 75 and the height of the waffle portion 72, which will be described later. The width of the insertion portion 71 substantially corresponds to the width of the flat multi-hole pipe 63, and when the flat multi-hole pipe 63 is inserted, friction is generated between the flat surface 63a of the flat multi-hole pipe 63 and the insertion portion 71. Occurs. The flat multi-hole tube 63 inserted into the insertion portion 71 of the fin 70 in this way is brazed and fixed to the fin 70.

The waffle portion 72 is formed between adjacent insertion portions 71 (between adjacent fin collars 71a) and near the center in the air flow direction. The waffle portion 72 is formed so that a portion that is raised in the plate thickness direction and a portion that is not raised are alternately repeated in the air flow direction, and the raised portion and the non-raised portion are continuous in the vertical direction. Is formed in. The waffle portion 72 is formed in a region from the middle vicinity in the air flow direction of the wind lower portion 70b of the fin 70 to straddling the communication portion 70a of the fin 70.

The communication side fin tab 73 is formed on the upstream side of each waffle portion 72 in the communication portion 70a of the fin 70 in the air flow direction in order to regulate the distance between the fins 70 arranged in the plate thickness direction on the windward side. The communication side fin tab 73 maintains a gap in the plate thickness direction in the vicinity of the communication portion 70a of the adjacent fins 70 by partially cutting up the fins 70.

The insertion-side fin tabs 74 are formed in the vicinity of the downstream end of the leeward 70b of the fins 70 in the air flow direction in order to regulate the distance between the fins 70 arranged in the plate thickness direction on the leeward side. Similar to the communication side fin tab 73, the insertion side fin tab 74 maintains a gap in the plate thickness direction in the vicinity of the leeward end of the adjacent fin 70 by partially cutting up the fin 70.

The slit 75 is a portion cut up from the main surface 79 in the plate thickness direction in order to improve the heat transfer performance of the fin 70, and is formed in the wind lower part 70b of the fin 70 on the downstream side of the waffle portion 72 in the air flow direction. ing. More specifically, in the present embodiment, the slit 75 is between adjacent insertion portions 71 (more specifically, between fin collars 71a), and between the waffle portion 72 and the insertion side fin tab 74. It is formed so that the longitudinal direction is the vertical direction (the arrangement direction of the flat multi-hole pipes 63). Further, a plurality of slits 75 (two in the present embodiment) are formed so as to be arranged in the air flow direction. As shown in FIG. 8, the slit 75 has an opening formed so as to be cut up on the same side in the plate thickness direction from the main surface 79 of the fin 70 on both the leeward side and the leeward side. .. The cut-up height (height in the plate thickness direction) of the slit 75 is formed so as to be 40% to 60% of the distance (fin pitch) between adjacent fins 70 from the viewpoint of improving heat transfer performance. It is preferably formed so as to be 45% to 55%, and most preferably half of the fin pitch. Since the length of the communication side fin tab 73 and the insertion side fin tab 74 in the plate thickness direction of the main surface 79 defines the fin pitch, the cut-up height of the slit 75 is the communication side fin tab 73 and the insertion side fin tab. It is preferably about half of these lengths of 74. In the present embodiment, the most raised portion of the waffle portion 72 is also configured to be located at about half of the fin pitch. Further, the width of the slit 75 in the vertical direction (direction in which the flat multi-hole pipes 63 are arranged) is configured to be shorter than the width of the waffle portion 72. In the present embodiment, the two slits 75 are provided so as to line up in the air flow direction, but the distance between these slits 75 in the air flow direction is the same as the width of one slit 75 in the air flow direction. It may be short.

The insertion-side rib 76 extends between the insertion portion 71 (more specifically, the fin collar 71a) and the slit 75 so that the insertion direction of the flat multi-hole tube 63 is the longitudinal direction. The insertion side ribs 76 are provided on both sides of the slit 75 in the vertical direction (direction in which the flat multi-hole pipes 63 are arranged). As shown in FIG. 7, the insertion-side rib 76 is inserted in the insertion direction from the contact portion P where the flat multi-hole tube 63 first hits when the flat multi-hole tube 63 is inserted into the insertion portion 71 of the fin 70. It is formed so as to extend linearly in parallel with the insertion direction toward the insertion progress side in the above. The insertion-side ribs 76 extend continuously so as to straddle all the slits 75 in the insertion direction of the flat multi-hole pipe 63, and extend further to the windward side than the slits 75 located on the windward side. More specifically, the slit 75 is located on the windward side of the slit 75 located on the windward side while straddling all the slits 75 from the downstream side of the insertion side fin tab 74 in the insertion direction of the flat multi-hole tube 63. It extends continuously in the insertion direction until it reaches.

In the present embodiment, the insertion side rib 76 is formed so as to be separated from the slit 75 and the fin collar 71a. The closest distance between the insertion-side rib 76 and the slit 75 is shorter than the closest distance between the insertion-side rib 76 and the fin collar 71a.

Further, as shown in FIG. 7, the insertion side rib 76 is formed by raising the main surface 79 of the fin 70 in the plate thickness direction. That is, the insertion-side rib 76 is configured to have a portion that rises with respect to the main surface 79 of the fin 70 and reaches the top, a top, and a portion that rises from the top to the main surface 79. ing. Here, the width of the insertion side rib 76 on the main surface 79 of the fin 70 in the direction perpendicular to the longitudinal direction is not particularly limited, but is 0.3 mm or more from the viewpoint of surely suppressing the buckling of the fin 70. It is preferably 0.5 mm or more, and more preferably 0.5 mm or more. Further, the width is preferably 2.0 mm or less, preferably 1.0 mm or less, from the viewpoint of facilitating securing the length of the slit 75 in the longitudinal direction for improving the heat transfer performance of the fin 70. Is more preferable. Further, the raised height of the insertion side rib 76 may be half or less of the height of the slit 75, more preferably 1.0 mm or less, and further preferably 05 mm or less.

The edge of the insertion-side rib 76 on the fin collar 71a side is continuous with the edge of the waffle portion 72 located on the windward side on the fin collar 71a side in the insertion direction.

The communication side rib 77 is formed so as to extend in the insertion direction both above and below the communication side fin tab 73 (both one side and the other side in the arrangement direction of the flat multi-hole tube 63). The edge of the communication-side rib 77 opposite to the communication-side fin tab 73 side is continuous with the edge of the insertion-side rib 76 on the fin collar 71a side and the edge of the waffle portion 72 on the fin collar 71a side in the insertion direction. There is. Further, the slit 75 is not formed at the position where the communication side rib 77 is provided in the insertion direction, and the width of the communication side rib 77 in the vertical direction is larger than the width of the insertion side rib 76 in the vertical direction. ing.

(6) Features (6-1)
The outdoor heat exchanger 11 of the present embodiment is manufactured by inserting a flat multi-hole tube 63 into the insertion portion 71 of the fin 70 and brazing and fixing the tube 63. Here, since the insertion portion 71 of the fin 70 has a shape corresponding to the outer edge of the flat multi-hole pipe 63, the insertion portion 71 of the fin 70 is the flat multi-hole pipe 63 when the flat multi-hole pipe 63 is inserted. It rubs against the flat surface 63a and stress acts. In particular, since the fin 70 of the present embodiment is formed with the fin collar 71a, the area where friction occurs with the flat surface 63a of the flat multi-hole pipe 63 is large, and a large stress acts on the fin 70. It tends to be. Since the fin 70 is formed with a slit 75 made of a cut-up piece in order to improve the heat transfer performance, the edge portion of the slit 75, particularly the edge portion of the edge portion, is close to the insertion portion 71. The strength of the portion is low, and there is a risk of buckling starting from the location due to the concentration of stress in the location.

On the other hand, in the outdoor heat exchanger 11 of the present embodiment, since the insertion side rib 76 is formed between the insertion portion 71 of the fin 70 and the slit 75, the fin 70 is inserted when the flat multi-hole pipe 63 is inserted. It is possible to alleviate the concentration of stress received in the vicinity of the slit 75 and suppress buckling starting from the vicinity of the slit 75 of the fin 70.

(6-2)
When inserting the flat multi-hole tube 63 into the fin 70, as shown in FIG. 7, the insertion proceeds starting from the contact portion P where the flat multi-hole tube 63 first hits among the insertion portions 71 of the fin 70. Side stress is likely to occur.

On the other hand, in the outdoor heat exchanger 11 of the present embodiment, the insertion side rib 76 provided in the fin 70 is formed on the insertion direction advancing side with respect to the contact portion P where the flat multi-hole pipe 63 first hits. Has been done. Therefore, the stress received by the fin 70 at the contact portion P is released to the advancing side in the insertion direction along the insertion side rib 76, and the concentration of the stress in the slit 75 of the fin 70 near the edge portion is relaxed. Will be possible.

In particular, the insertion-side ribs 76 extend continuously so as to straddle all of the plurality of slits 75 formed in the fins 70 so as to line up in the air flow direction. Therefore, stress concentration can be suppressed at the outer edges of any of the slits 75 provided in the fins 70.

Further, since the insertion side ribs 76 are provided on both sides of the slit 75 in the vertical direction (arrangement direction of the flat multi-hole pipe 63), it is possible to suppress buckling at each edge of the slit 75. It has become.

(6-3)
The outdoor heat exchanger 11 of the present embodiment is formed so that the cut-up height (height in the plate thickness direction) of the slit 75 is 40% to 60% of the distance (fin pitch) between adjacent fins 70. Has been done. Therefore, not only the air flow having the highest flow velocity passing near the intermediate portion between the adjacent fins 70 can be applied to the slit 75, but also the cut-up height can be sufficiently secured, so that the heat transfer performance is good. Can be.

Here, in the outdoor heat exchanger 11 of the above embodiment, as shown in FIG. 8, the insertion side rib 76 is raised from the main surface 79 of the fin 70 toward the slit 75 side from the fin collar 71a to the top. After reaching the main surface 79, it is formed to rise so as to descend until it reaches the main surface 79 again. Therefore, the slit 75 is directly cut up from the main surface 79 toward one side in the plate thickness direction. That is, when a rising surface raised from the main surface 79 on one side in the plate thickness direction is formed, it is not cut up from the rising surface toward one side in the plate thickness direction. Absent.

Therefore, since the distance between the main surfaces 79 of the adjacent fins 70 (particularly, the distance between the main surfaces 79 around the slit 75) can be secured widely, the slit 75 is cut to the intermediate height position of the distance. When it is raised, the cut-up height of the slit 75 can be secured sufficiently high (the slit 75 is cut up to about the intermediate height position between the rising surface and the adjacent fin 70). It is possible to secure a sufficiently high cut-up height compared to the case where the slit is raised). As a result, the heat transfer performance of the fin 70 can be improved.

(7) Modified Example Although an example of the embodiment of the present invention has been described in the above embodiment, the above embodiment is not intended to limit the present invention and is not limited to the above embodiment. As a matter of course, the present invention also includes aspects that are appropriately modified without departing from the spirit of the present application.

(7-1) Modification A
In the above embodiment, a structure in which the leeward end of the flat multi-hole pipe 63 projects further leeward than the leeward 70b of the fin 70 has been described as an example.

However, the relationship between the width of the insertion portion 71 of the fin 70 and the width of the flat multi-hole pipe 63 in the air flow direction is not limited to this relationship, and for example, as shown in FIG. 10, the leeward 70b of the fin 70 A heat exchanger having a structure in which the leeward end of the flat multi-hole pipe 63 projects further leeward than the leeward end of the flat multi-hole pipe 63 may be used.

(7-2) Modification B
In the above embodiment, the case where two slits 75 are formed side by side in the air flow direction in the fin 70 has been described as an example.

However, the number of slits 75 provided in the fin 70 is not limited to this, and for example, as shown in FIG. 11, four slits 75 may be formed side by side in the air flow direction. When many slits 75 are provided in this way, the heat transfer performance of the fins 70 can be further improved. In this case, the length of the waffle portion 72 in the air flow direction is formed shorter by the amount of the increase in the slit 75 as compared with the fin 70 of the above embodiment. Further, also in this example, since the insertion side rib 76 extends continuously so as to straddle all four slits 75 in the insertion direction, it is possible to suppress buckling at the edge of each slit 75. It has become. Even if the number of slits 75 provided in the fins 70 increases, the strength of the fins 70 when the insertion side ribs 76 extending so as to straddle each slit 75 in the insertion direction of the flat multi-hole tube 63 are provided. Was not reduced, and it was confirmed by analysis that buckling during insertion could be suppressed.

(7-3) Modification C
In the above embodiment, a case where two slits 75 and a waffle portion 72 are formed side by side in the air flow direction in the fin 70 has been described as an example.

However, for example, as shown in FIG. 12, instead of the waffle portion 72, a fin 70 to which a slit 75 is further added (eight slits 75 are formed side by side in the air flow direction) may be used. In this case, the insertion-side rib 76 of the above embodiment can be extended to the upstream side in the air flow direction, and can be provided so as to extend so as to straddle all the slits 75 in the insertion direction.

(7-4) Modification D
In the outdoor heat exchanger 11 of the above embodiment, as the cut-up piece formed on the fin 70, a slit 75 having an opening formed on the same side in the plate thickness direction on both the upstream side and the downstream side in the air flow direction is provided. The explanation was given as an example.

However, the cut-up piece formed on the fin 70 is not particularly limited as long as it can improve the heat transfer performance. For example, only the leeward side is open and the leeward side is not open and is gentle on the main surface 79. A louver formed so as to be connected to the louver may be used.

Further, as a cut-up piece formed on the fin 70, an opening is formed on one side of the main surface 79 on the leeward side while inclining the cut-up portion with respect to the main surface 79, and the main surface 79 is formed on the leeward side. An inclined slit formed so as to generate an opening on the opposite side of the may be used.

Since the insertion side rib 76 is formed at any of these edges, it is possible to suppress buckling when the flat multi-hole tube 63 is inserted.

(7-5) Modification E
In the outdoor heat exchanger 11 of the above embodiment, the insertion side rib 76 extending linearly in the insertion direction between the slit 75 of the fin 70 and the insertion portion 71 has been described as an example.

However, the insertion-side rib 76 provided between the slit 75 of the fin 70 and the insertion portion 71 is not limited to one that extends linearly in the insertion direction, and for example, approaches or slits the slit 75 as the insertion progress direction. Those that extend at an angle so as to move away from 75 may be used. Further, the insertion side rib 76 does not have to extend linearly, and may have a meandering shape so that the insertion direction is the longitudinal direction, for example.

1 Air conditioner 2 Outdoor unit 11 Outdoor heat exchanger (heat exchanger)
63 Flat multi-hole tube (flat tube)
63a Flat surface 63b Passage (refrigerant flow path)
63y Downwind exposed part 70 Fin 70a Communication part 70b Windward part 71 Insertion part 71a Fin collar 72 Waffle part 73 Connecting side fin tab 74 Inserting side fin tab 75 Slit (cut piece)
76 Insertion side rib (rib)
77 Connecting side rib

Patent Document 1: Japanese Unexamined Patent Publication No. 2012-233680

Claims (6)

A plurality of flat tubes (63) arranged with the flat surfaces (63a) facing each other,
A plurality of fins (71) having a plurality of insertion portions (71) extending along an insertion direction intersecting the direction in which the flat tubes are arranged and the longitudinal direction of the flat tubes, into which at least a part of the flat tubes is inserted. 70) and
With
The fin has a cut-up piece (75) cut up in the plate thickness direction between the plurality of insertion portions and a rib (76) formed between the insertion portion and the cut-up piece. Have and
The fin has a plurality of the cut pieces so as to be lined up in the insertion direction of the flat tube.
The rib extends continuously along the insertion direction of the flat tube between the insertion portion and the plurality of cut-up pieces.
Heat exchanger (11). The rib is formed at least on the insertion progress side in the insertion direction from the portion (P) where the flat tube first hits when the flat tube is inserted into the fin among the insertion portions of the fin.
The heat exchanger according to claim 1. The rib extends further to the insertion progress side than the cut up piece located on the insertion progress side most in the insertion direction of the flat tube among the plurality of cut up pieces located between the adjacent insertion portions. Extending like
The heat exchanger according to claim 1 or 2. The fin is formed so as to border the insertion portion, and has a fin collar (71a) facing the flat surface of the flat tube.
The rib is formed between the fin collar and the cut-up piece.
The heat exchanger according to any one of claims 1 to 3. The fin has ribs formed between the cut-up piece and the insertion portions on both sides.
The heat exchanger according to any one of claims 1 to 4. The rib is formed by raising the fin in the plate thickness direction.
The heat exchanger according to any one of claims 1 to 5.

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